The present invention relates to a photo-induced phase transition organic material, more particularly to a photo-induced phase transition organic material composed of a diheteroarylethene-based compound in which the phase transition occurs in response to light irradiation in a crystalline state, especially even in a single-crystalline state.
A photochromic material, which means the material containing a sort of molecule or molecular assembly from which two isomers having different colors are reversibly formed due to the action of light, has been expected as a photo-functional material since a variety of its physical properties, such as not only the color, but also the dielectric constant, the oxidation/reduction potential, etc., reversibly varies with light irradiation in connection with its photo-chromic reaction. Both photochromic molecules and molecular assemblies conventionally employed are to be transferred with light irradiation from colorless state to one-colored state in a solution or a macromolecular medium, such as red and blue, while method of applying various chemical modifications to the photochromic molecules have been studied in order to obtain the photochromic material which can develop various colors.
The present invention has arisen from the detailed analysis of the mechanism of the photochromic reaction of diheteroarylethene-based compound which does not need any dispersion medium, and the object of the present invention is to provide a photo-induced phase transition organic material which utilizes the photochromic reaction of diheteroarylethene-based compound.
The photo-induced phase transition organic material of the present invention is composed of a diheteroarylethene-based compound within which the photochromic reaction occurs in the crystalline state, especially in the single-crystalline state.
On the other hand, conventional photochromic compound undergoes the photochromic reaction in a state where they are dispersed or dissolved in a macromolecular-film or a solvent, and there has been no photochromic compound which stably undergoes the photochromic reaction in a crystalline phase like the photochromic material of the present invention.